WO2021238970A1 - 滤波器、双工器、多工器以及通信设备 - Google Patents

滤波器、双工器、多工器以及通信设备 Download PDF

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Publication number
WO2021238970A1
WO2021238970A1 PCT/CN2021/095993 CN2021095993W WO2021238970A1 WO 2021238970 A1 WO2021238970 A1 WO 2021238970A1 CN 2021095993 W CN2021095993 W CN 2021095993W WO 2021238970 A1 WO2021238970 A1 WO 2021238970A1
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Prior art keywords
resonator
frequency
filter
frequency filter
low
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PCT/CN2021/095993
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English (en)
French (fr)
Inventor
边子鹏
庞慰
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诺思(天津)微系统有限责任公司
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Publication of WO2021238970A1 publication Critical patent/WO2021238970A1/zh

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/01—Frequency selective two-port networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/46—Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/005—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges
    • H04B1/0053—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges with common antenna for more than one band
    • H04B1/0057—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission adapting radio receivers, transmitters andtransceivers for operation on two or more bands, i.e. frequency ranges with common antenna for more than one band using diplexing or multiplexing filters for selecting the desired band
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits
    • H04B1/401—Circuits for selecting or indicating operating mode

Definitions

  • the present invention relates to the technical field of filters, in particular to a filter, a duplexer, a multiplexer and a communication device.
  • FIG. 1 is a schematic diagram of a structure of an acoustic wave filter in the prior art.
  • this filter 100 there are inductors L1, L2, and multiple resonators (usually called series resonators) S11 to S14 between the input terminal T1 and the output terminal T2.
  • the connection point of each series resonator and the ground terminal Resonators P12 to P14 (commonly called parallel resonators) and inductances L3 to L5 are respectively provided on multiple branches (usually called parallel branches) of.
  • a mass load layer is added to each parallel resonator, so that the frequency of the parallel resonator and the frequency of the series resonator are different to form the passband of the filter.
  • FIG. 2 is a schematic cross-sectional view of a conventional film bulk acoustic resonator.
  • 31 is a semiconductor substrate material
  • 35 is an air cavity obtained by etching
  • the bottom electrode 33 of the thin film bulk acoustic resonator is deposited on the semiconductor substrate 31.
  • 32 is a piezoelectric film material
  • 34 is a top electrode.
  • the area selected by the dashed line is the overlapping area of 35 air cavity, 34 top electrode, 33 bottom electrode and 32 piezoelectric layer, which is the effective area of resonance.
  • the material of the top electrode and the bottom electrode can be made of gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), titanium tungsten (TiW), aluminum (Al) ), or titanium (Ti) and other similar metals;
  • the material of the piezoelectric layer can be aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), lithium niobate (LiNbO3), quartz (Quartz ), potassium niobate (KNbO3) or lithium tantalate (LiTaO3), etc.
  • the thickness of the piezoelectric film is generally less than 10 microns.
  • the aluminum nitride film is in a polycrystalline form or a single crystal form, and the growth method is thin film sputtering or metal organic chemical vapor deposition (MOCVD).
  • Fig. 3 is a schematic diagram of impedance frequency characteristics of a bulk acoustic wave resonator (BAW) according to the prior art.
  • the main resonance of the BAW resonator has two resonant frequency points: one is the fs when the impedance of the resonant circuit reaches a minimum, and fs is defined as the series resonance frequency of the resonator; the other is when the impedance of the resonant circuit reaches the extreme When the value of fp is large, fp is defined as the parallel resonance frequency of the resonator.
  • the BAW resonator will produce high-order resonance at the high-frequency end while generating the main resonance. This high-order resonance is usually unnecessary and should be suppressed.
  • FIG. 4 is a schematic diagram of the circuit structure of a duplexer according to the prior art.
  • the dashed frame D1 is the low frequency filter chip of the duplexer
  • the dashed frame D2 is the high frequency filter chip of the duplexer.
  • Both the low frequency filter and the high frequency filter are piezoelectric filters with a ladder structure.
  • the low frequency filter includes series resonators S11 to S14 and parallel resonators P11 to P13.
  • the high-frequency filter includes series resonators S21 to S24 and parallel resonators P21 to P24.
  • L1 and L2 are the low-frequency filter signal input and output inductances
  • L5 and L6 are the high-frequency filter signal input and output inductances
  • L3 and L4 are the parallel branch grounding inductances of the low-frequency filter
  • L7 and L8 are the high-frequency filter's inductances.
  • LM is the matching inductance at the antenna end of the duplexer.
  • the present invention provides a filter, a duplexer, a multiplexer, and a communication device.
  • the SC circuit formed by the series connection of a special resonator and an inductor is used to improve the out-of-band suppression performance of the filter, and to improve the duplexer and the multiplexer. The isolation of the worker.
  • a filter is provided.
  • the filter of the present invention is a ladder structure, including a series path and a plurality of parallel branches, the resonator in the filter is an acoustic wave resonator, and the plurality of parallel branches includes 1 SC circuit, and:
  • the SC circuit includes a resonator and a series-connected inductor, and the main resonance frequency and high-order resonance frequency of the resonator in the SC circuit are both outside the passband of the filter; or, the SC circuit includes a resonator Group and series inductors, the resonator group contains multiple resonators, at least one of the resonator resonant frequency is different from the resonant frequency of other resonators, and the main resonant frequency and high-order resonant frequency of each resonator All are outside the passband of the filter.
  • the frequency of the series resonance formed by the equivalent capacitance of the 1 resonator or the resonator group and the series-connected inductor is located in the out-of-band suppression frequency band of the filter.
  • a first duplexer which includes a low-frequency filter and a high-frequency filter, and the high-frequency filter in the duplexer is the filter described in the present invention.
  • the main resonance frequency is outside the passband of the high frequency filter of the duplexer.
  • the resonator or resonator group in the SC circuit is arranged on the chip where the high-frequency filter is located, and the mass load in the resonator or resonator group makes the main resonance frequency of the resonator or each of the resonator group
  • the main resonance frequency of the resonator is at the low frequency end outside the passband of the high frequency filter.
  • the resonator or resonator group in the SC circuit is arranged on the chip where the low-frequency filter is located, and the thickness of each film layer in the resonator or resonator group is the same as the film layer thickness of the series resonator in the low-frequency filter Or close, make the main resonance frequency of the resonator or the main resonance frequency of each resonator in the resonator group within the passband of the low-frequency filter.
  • the SC circuit in the high-frequency filter is connected to the high-frequency filter signal input/output end of the duplexer or a certain node of the series path of the high-frequency filter.
  • a second type of duplexer is provided, the duplexer includes a low frequency filter and a high frequency filter, and the low frequency filter in the duplexer is the filter described in the present invention.
  • the duplexer of the present invention includes a low-frequency filter and a high-frequency filter, and the low-frequency filter in the duplexer is the filter described in the present invention.
  • the main resonance frequency is outside the passband of the low frequency filter of the duplexer.
  • the resonator or resonator group in the SC circuit is arranged on the chip where the low-frequency filter is located, and the mass load in the resonator or resonator group makes the main resonance frequency of the resonator or each of the resonator groups resonate
  • the main resonance frequency of the filter is at the low-frequency end outside the passband of the low-frequency filter.
  • the resonator or resonator group in the SC circuit is provided on the chip where the high-frequency filter is located, and the thickness of each film layer in the resonator or resonator group is the same as the film layer of the series resonator in the high-frequency filter.
  • the thickness is the same or similar, so that the main resonance frequency of the resonator or the main resonance frequency of each resonator in the resonator group is within the passband of the high-frequency filter.
  • the SC circuit in the low-frequency filter is connected to the low-frequency filter signal input/output end of the duplexer or a certain node of the low-frequency filter series path.
  • a third type of duplexer includes a low-frequency filter and a high-frequency filter. Both the high-frequency filter and the low-frequency filter in the duplexer are made by the present invention. The filter described.
  • the main resonance frequency of the resonator of the SC circuit in the low frequency filter or the main resonance frequency of each resonator in the resonator group is outside the passband of the low frequency filter.
  • the main resonance frequency of the resonator of the SC circuit in the high-frequency filter or the main resonance frequency of each resonator in the resonator group is outside the passband of the high-frequency filter.
  • the resonator or resonator group in the SC circuit in the low-frequency filter is arranged on the chip where the low-frequency filter is located, and the mass load in the resonator or resonator group makes the main resonance frequency or resonance of the resonator
  • the main resonance frequency of each resonator in the high-frequency filter is at the low-frequency end outside the passband of the low-frequency filter;
  • the mass load in the resonator or resonator group makes the main resonance frequency of the resonator or the main resonance frequency of each resonator in the resonator group within the passband of the low-frequency filter.
  • the resonator or group of resonators in the SC circuit in the low frequency filter and the high frequency filter are both set on the chip where the low frequency filter is located; the resonator or resonator in the SC circuit of the low frequency filter
  • the mass load in the group makes the main resonance frequency of the resonator or the main resonance frequency of each resonator in the resonator group at the low-frequency end outside the passband of the low-frequency filter;
  • the resonator in the SC circuit of the high-frequency filter Or the thickness of each film in the resonator group is the same or similar to that of the series resonator in the low-frequency filter, so that the main resonant frequency of the resonator or the main resonant frequency of each resonator in the resonator group is in the low-frequency filter In the passband.
  • the resonator or resonator group in the SC circuit in the low-frequency filter is arranged on the chip where the high-frequency filter is located, and the thickness of each film layer is the same as or the thickness of the film layer of the series resonator in the high-frequency filter. Similar; the resonator or resonator group in the SC circuit in the high-frequency filter is set on the chip where the low-frequency filter is located, and the thickness of each film layer is the same as or similar to that of the series resonator in the low-frequency filter.
  • the SC circuit in the high-frequency filter is connected to the high-frequency filter signal input/output end of the duplexer or a node of the series path of the high-frequency filter; the SC circuit in the low-frequency filter is connected to the duplexer The low-frequency filter signal input/output of the low-frequency filter or a node in the series path of the low-frequency filter.
  • a multiplexer including the filter or duplexer of the present invention.
  • a communication device including the filter or duplexer of the present invention.
  • Fig. 1 is a schematic diagram of a structure of an acoustic wave filter according to the prior art
  • Figure 2 is a schematic cross-sectional view of a conventional film bulk acoustic resonator
  • Fig. 3 is a schematic diagram of impedance frequency characteristics of a bulk acoustic wave resonator (BAW) according to the prior art
  • FIG. 4 is a schematic diagram of the circuit structure of a duplexer according to the prior art
  • FIG. 5 is a schematic diagram of the basic structure of a circuit for suppressing high-order resonance of a bulk acoustic wave resonator according to an embodiment of the present invention
  • FIG. 6 is a schematic diagram of an impedance characteristic curve of a resonator and an impedance characteristic curve of an SC circuit according to an embodiment of the present invention
  • FIG. 7 is a schematic diagram of the circuit structure of the filter in the first embodiment of the present invention.
  • FIG. 8 is a comparison between the insertion loss frequency characteristics (solid line) of the filter in the first embodiment of the present invention and the insertion loss frequency characteristics (dashed line) of the filter shown in the prior art as a comparative example;
  • Fig. 9 is a comparison between the insertion loss frequency characteristic (solid line) of the filter in the first embodiment of the present invention and the impedance characteristic (dashed line) of the SC circuit;
  • FIG. 10 is a schematic diagram of the circuit structure of the filter in the second embodiment of the present invention.
  • FIG. 11 is a schematic diagram of the circuit structure of a duplexer according to a third embodiment of the present invention.
  • FIG. 12 is a schematic diagram of the circuit structure of a duplexer according to a fourth embodiment of the present invention.
  • FIG. 13 is a schematic diagram of the insertion loss frequency characteristics of the duplexer circuits according to the third embodiment and the fourth embodiment of the present invention.
  • Fig. 14 is an enlarged schematic diagram of area A in Fig. 13;
  • 16 is a schematic diagram of the circuit structure of a duplexer according to a fifth embodiment of the present invention.
  • 17 is a schematic diagram of the insertion loss frequency characteristic of the duplexer circuit shown in the fifth embodiment of the present invention.
  • Fig. 18 is an enlarged schematic diagram of area A in Fig. 17;
  • FIG. 19 is an enlarged schematic diagram of area B and area C in FIG. 17;
  • FIG. 20 is a schematic diagram of the circuit structure of a duplexer according to a sixth embodiment of the present invention.
  • 21 is a schematic diagram of the insertion loss frequency characteristic of the duplexer circuit according to the sixth embodiment of the present invention.
  • FIG. 22 is an enlarged schematic diagram of area A of 21;
  • FIG. 23 is a schematic diagram of the comparison of the isolation characteristics of the duplexer in the sixth embodiment of the present invention and the prior art
  • FIG. 24 is a schematic diagram of the circuit structure of a duplexer according to a seventh embodiment of the present invention.
  • 25 is a schematic diagram of the circuit structure of a duplexer according to an eighth embodiment of the present invention.
  • 26 is a schematic diagram of the frequency insertion loss characteristics of the duplexer circuits according to the seventh embodiment and the eighth embodiment of the present invention.
  • Fig. 27 is an enlarged schematic diagram of the A-L area and A-H area in Fig. 26;
  • 29 is a schematic diagram of the circuit structure of a duplexer according to a ninth embodiment of the present invention.
  • FIG. 30 is a schematic diagram of the insertion loss frequency characteristic of the duplexer circuit according to the ninth embodiment of the present invention.
  • Fig. 31 is an enlarged schematic diagram of the A-T area and the A-R area in Fig. 30;
  • FIG. 32 is a schematic diagram of the isolation characteristics of the duplexer in the ninth embodiment of the present invention compared with that in the prior art.
  • FIG. 5 is a schematic diagram of the basic structure of a circuit for suppressing high-order resonance of a bulk acoustic wave resonator according to an embodiment of the present invention.
  • the circuit in FIG. 5 is referred to as an SC circuit.
  • HSC circuit when the circuit is applied to the high-frequency filter in the duplexer, the circuit is also called HSC circuit.
  • the circuit is also called an LSC circuit.
  • Figure 5 shows that the SC circuit includes a resonator P01 and a series-connected inductor (inductor) LS.
  • the resonator P01 can be a resonator group composed of multiple resonators connected (including series and/or parallel), and the inductor LS can also be a series and/or parallel body of multiple inductors.
  • the series Inductance refers to the series and/or parallel body connected in series with a single resonator or connected in series with a group of resonators.
  • FIG. 6 is a schematic diagram of the impedance characteristic curve of the resonator and the impedance characteristic curve of the SC circuit according to the embodiment of the present invention.
  • the solid line in the figure represents the impedance of the SC circuit, and the dashed line represents the impedance of a single resonator.
  • the characteristic of the SC circuit is that the resonant frequency (including the main resonance and high-order resonance) of the resonator P01 in the SC circuit is set outside the passband of the filter.
  • the series resonance frequency formed by the plate capacitance of the resonator P01 and the LS inductance cascaded with it occurs in the frequency band where the filter needs to improve the out-of-band suppression.
  • the two curves are placed in the same coordinate system for comparison. It can be seen that the impedance of the SC circuit shown by the solid line is in the series resonance formed by the plate capacitance of the resonator P01 and the LS inductance cascaded with it. Near the frequency point is a minimum value, so the series resonance generated by the SC circuit at the high frequency end can effectively improve the suppression characteristics of the frequency band where it is located.
  • the product of the plate capacitance of the resonator P01 and the LS inductance cascaded with it is determined accordingly.
  • Fig. 7 is a schematic diagram of the circuit structure of the filter in the first embodiment of the present invention.
  • the filter 600 is a piezoelectric filter with a ladder structure mainly composed of series resonators S11 to S14, parallel resonators P12 to P14, and an SC circuit.
  • T1 is the signal input port
  • T2 is the signal output port
  • L1 and L2 are the input and output inductances
  • L3, L4, and L5 are the parallel branch grounding inductances.
  • One end of the SC circuit in the figure is grounded, and the other end can be connected to any node in the series branch of the filter.
  • FIG. 8 is a comparison of the insertion loss frequency characteristic (solid line) of the filter in the first embodiment of the present invention and the insertion loss frequency characteristic (dashed line) of the filter shown in the prior art as a comparative example. It can be seen from FIG. 8 that compared with the prior art, the filter in the first embodiment has significantly improved out-of-band suppression at the A region, the B1 region, the B2 region, and the C region.
  • Fig. 9 is a comparison between the insertion loss frequency characteristic (solid line) of the filter in the first embodiment of the present invention and the impedance characteristic (dashed line) of the SC circuit. From Figure 9 we can see how the SC circuit affects the filter performance. As shown in Figure 9, area A corresponds to the frequency band near the series resonance frequency of the main resonance of resonator P01 in the SC circuit, area B1 corresponds to the frequency band near the series resonance frequency of the first high-order resonance of resonator P01 in the SC circuit, and area B2 corresponds to The frequency band near the series resonance frequency of the second high-order resonance of the resonator P01 in the SC circuit, and the C region corresponds to the frequency band near the series resonance frequency formed by the plate capacitor of the resonator P01 in the SC circuit and the LS inductor cascaded with it.
  • the main resonance, high-order resonance of the resonator in the SC circuit of the present invention, and the series resonance of the plate capacitance of the resonator and the inductance cascaded therewith are all reasonably utilized to improve the overall performance of the device.
  • the resonator can be multiple connected bodies.
  • FIG. 10 is based on the circuit structure of the filter in the second embodiment of the present invention. Schematic. As shown in FIG. 10, the difference between the second embodiment and the first embodiment lies in the structure of the resonator in the SC circuit.
  • the resonators in the SC circuit are split in series, which may be equal area split or non-equal area split, but the main resonance frequencies of the resonator P01 and the resonator P02 are different.
  • the low-frequency filter and/or the high-frequency filter may be the above-mentioned filter including the SC circuit, which will be described in detail below.
  • Fig. 11 is a schematic diagram of a circuit structure of a duplexer according to a third embodiment of the present invention.
  • an SC circuit HSC circuit
  • HSC can be installed in parallel on any node of the high-frequency filter series path, but it is best to set it in the position shown in Figure 11, because HSC The farther the circuit is from the antenna end of the duplexer, the smaller the effect on the convergence of the duplexer.
  • the resonator P02 in the HSC circuit can be shifted by adding a mass load so that its main resonant frequency is set at the low-frequency end outside the passband of the high-frequency filter, and in particular, its main resonant frequency can be set to the pass-band of the low-frequency filter. In-band.
  • Fig. 12 is a schematic diagram of a circuit structure of a duplexer according to a fourth embodiment of the present invention.
  • the resonator P02 in the HSC circuit can also be set on the chip of the low-frequency filter.
  • the layer thickness is the same or similar, so that the main resonance frequency is at the low frequency end outside the pass band of the high frequency filter (including the frequency band where the pass band of the low frequency filter is located).
  • FIG. 13 is a schematic diagram of the insertion loss frequency characteristics of the duplexer circuits according to the third embodiment and the fourth embodiment of the present invention, and compares the insertion loss frequency characteristics of the high-frequency filter in the embodiment with the existing frequency characteristics of the second comparative example. The frequency characteristics of the insertion loss of the high-frequency filter in the technical duplexer are compared.
  • the solid line marked by the small box is the insertion loss curve of the low-frequency filter in the third embodiment, the fourth embodiment and the prior art. Because the SC circuit is not added, the three curves are consistent.
  • the solid line marked by the small circle is the insertion loss curve of the high-frequency filter of the third embodiment and the fourth embodiment
  • the dashed line is the insertion loss curve of the high-frequency filter in the prior art
  • the unmarked solid line is the first The impedance frequency characteristics of the HSC circuit in the third embodiment and the fourth embodiment.
  • Zone A suppresses the main resonance of the resonator in the corresponding HSC circuit
  • zone B suppresses the high-order resonance of the resonator in the HSC circuit
  • zone C suppresses the corresponding HSC circuit.
  • FIG. 14 is an enlarged schematic diagram of area A in FIG. 13, and FIG. 15 is a schematic diagram of isolation characteristics of the third embodiment and the fourth embodiment of the present invention compared with the prior art.
  • FIG. 14 and Figure 15 if the main resonance of the resonator in the HSC circuit falls within the passband of the low-frequency filter, the out-of-band suppression characteristics of the high-frequency filter in the frequency band where the passband of the low-frequency filter is located can be effectively improved ( Shown in area A in Fig. 14) and the isolation characteristics of the frequency band where the passband of the low-frequency filter is located (shown in area D in Fig. 15).
  • Fig. 16 is a schematic diagram of a circuit structure of a duplexer according to a fifth embodiment of the present invention.
  • the LSC circuit is set in the low-frequency filter.
  • LSC can be placed in parallel on any node of the low-frequency filter series path, but it is best to set the position as shown in Figure 16, because the LSC circuit is far from the antenna of the duplexer The farther the end is, the smaller the impact on the convergence of the duplexer.
  • the resonator P01 in the LSC circuit can be shifted by setting the mass load so that its main resonance frequency is at the low frequency end outside the passband of the low frequency filter.
  • FIG. 17 is a schematic diagram of the insertion loss frequency characteristics of the duplexer circuit shown in the fifth embodiment of the present invention, and compares the insertion loss frequency characteristics of the low-frequency filter in the fifth embodiment with the insertion loss frequency of the low-frequency filter in the prior art The characteristics are compared.
  • Fig. 18 is an enlarged schematic diagram of area A in Fig. 17.
  • FIG. 19 is an enlarged schematic diagram of area B and area C in FIG. 17.
  • the dotted line is the insertion loss curve of the low-frequency filter in the prior art
  • the solid line marked by the small box is the insertion loss curve of the high-frequency filter in the fifth embodiment and the prior art
  • the small circle is marked
  • the solid line is the insertion loss curve of the low-frequency filter in the fifth embodiment
  • the unmarked solid line is the impedance frequency characteristic of the LSC circuit in the fifth embodiment.
  • Zone A suppresses the main resonance of the resonator in the corresponding LSC circuit
  • zone B Suppress the high-order resonance of the resonator in the corresponding LSC circuit, and suppress the series resonance formed by the plate capacitance of the resonator P01 in the corresponding LSC circuit and the inductance cascaded with it in the C zone.
  • the duplexer in the fifth embodiment due to the LSC circuit, the out-of-band suppression characteristics of the low-frequency filter are significantly improved in the A region, the B region, and the C region.
  • Fig. 20 is a schematic diagram of a circuit structure of a duplexer according to a sixth embodiment of the present invention.
  • the LSC circuit is set in the low-frequency filter.
  • the LSC can be arranged in parallel on any node of the low-frequency filter series path, but it is better to set the position as shown in Fig. 20.
  • the resonator P01 in the LSC circuit is made on the high-frequency filter chip.
  • the thickness of each layer of the Stack of the resonator in the LSC circuit is the same or similar to that of the series resonator in the high-frequency filter, so that its main resonance frequency is at In the passband of the high-frequency filter.
  • FIG. 21 is a schematic diagram of the insertion loss frequency characteristics of the duplexer circuit according to the sixth embodiment of the present invention, and compares the insertion loss frequency characteristics of the low-frequency filter in the sixth embodiment with the insertion loss of the low-frequency filter in the prior art The frequency characteristics are compared.
  • the dotted line in the figure is the insertion loss curve of the low-frequency filter in the prior art
  • the solid line marked by the small box is the insertion loss curve of the sixth embodiment and the high-frequency filter in the prior art
  • the solid line marked by the small circle is the sixth implementation.
  • the unmarked solid line is the impedance frequency characteristic of the LSC circuit in the sixth embodiment.
  • Zone A suppresses the main resonance of the resonator in the LSC circuit
  • zone B suppresses the resonance in the LSC circuit.
  • the high-order resonance of the device, the C zone suppresses the series resonance formed by the plate capacitance of the resonator P01 in the corresponding LSC circuit and the inductance cascaded with it. It can be seen from the figure that due to the LSC circuit of the duplexer in the sixth embodiment, the out-of-band suppression characteristics of the low-frequency filter are significantly improved in the A region, the B region, and the C region.
  • FIG. 22 is an enlarged schematic diagram of area A of 21.
  • FIG. FIG. 23 is a schematic diagram of the comparison of the isolation characteristics of the duplexer in the sixth embodiment of the present invention and the prior art. The dotted line in the figure corresponds to the prior art, and the solid line marked by the small circle corresponds to the sixth embodiment.
  • the main resonance frequency of the resonator P01 is within the passband of the high-frequency filter, which can effectively improve the out-of-band suppression characteristics of the low-frequency filter in the frequency band where the passband of the high-frequency filter is located ( Figure 22 Shown in area A) and the isolation characteristics of the frequency band where the passband of the high-frequency filter is located (shown in area D in Figure 23).
  • Fig. 24 is a schematic diagram of the circuit structure of a duplexer according to a seventh embodiment of the present invention.
  • the LSC circuit is installed in the low-frequency filter, while the HSC circuit is installed in the high-frequency filter.
  • the LSC circuit can be set in parallel on any node of the low-frequency filter series path, and the HSC circuit can be set in parallel on any node of the high-frequency filter series path, but the better way is that the LSC circuit and HSC circuit are set as shown in Figure 24 It is far away from the antenna end position of the duplexer, so that the convergence of the duplexer is less affected.
  • the resonator P01 in the LSC circuit is built on the low-frequency filter chip, and the main resonance frequency is placed on the low-frequency end outside the passband of the low-frequency filter by adding a mass load, and the resonator P02 in the HSC circuit is built on the high-frequency filter chip.
  • the main resonance frequency can be set within the passband of the low-frequency filter.
  • Fig. 25 is a schematic diagram of a circuit structure of a duplexer according to an eighth embodiment of the present invention.
  • the HSC circuit in the eighth embodiment is built on the low-frequency filter chip, and the thickness of each layer of the Stack of the resonator in the HSC circuit is the same as or the thickness of the film layer of the series resonator in the low-frequency filter. Close, make its main resonance within the passband of the low-frequency filter.
  • FIG. 26 is a schematic diagram of the frequency insertion loss characteristics of the duplexer circuits according to the seventh embodiment and the eighth embodiment of the present invention, and the frequency characteristics of the insertion loss are compared with those of the duplexer in the prior art. It can be seen from the figure that due to the arrangement of the LSC circuit and HSC circuit in the duplexers of the seventh and eighth embodiments, the out-of-band suppression characteristics of the low-frequency filter are significantly improved in the AL, BL, and CL regions. At the same time, high The out-of-band suppression characteristics of the frequency filter are significantly improved in the AH, BH, and CH regions.
  • Fig. 27 is an enlarged schematic diagram of the area A-L and the area A-H in Fig. 26. 28 is a schematic diagram of the isolation characteristics of the duplexer in the seventh and eighth embodiments of the present invention and the prior art.
  • the unmarked solid line in the figure corresponds to the prior art, and the solid line marked by the small circle corresponds to the seventh embodiment example.
  • the main resonance frequency of the resonator P02 is set in the passband of the low-frequency filter, which can effectively improve the out-of-band suppression characteristics of the high-frequency filter in the frequency band where the passband of the low-frequency filter is located ( Figure 27) (Shown in the AH area) and the isolation characteristics of the frequency band where the passband of the low-frequency filter is located (shown in the DH area in Figure 28).
  • Fig. 29 is a schematic diagram of a circuit structure of a duplexer according to a ninth embodiment of the present invention.
  • the LSC circuit is set in the low-frequency filter, while the HSC circuit is set in the high-frequency filter.
  • the LSC circuit can be arranged in parallel on any node of the low-frequency filter series path, and the HSC circuit can be arranged in parallel on any node of the high-frequency filter series path, but the better way is to set the LSC circuit and HSC circuit as shown in Figure 29 Keep away from the antenna end of the duplexer.
  • the resonator P01 in the LSC circuit is arranged on the high-frequency filter chip, and the resonator P02 in the HSC circuit is arranged on the low-frequency filter chip.
  • the main resonance frequency of the resonator P01 in the LSC circuit is set in the passband of the high-frequency filter
  • the main resonance frequency of the resonator P02 in the HSC circuit is set in the passband of the low-frequency filter.
  • FIG. 30 is a schematic diagram of the insertion loss frequency characteristics of the duplexer circuit according to the ninth embodiment of the present invention, and compares the insertion loss frequency characteristics with the prior art.
  • the short dashed line and the dotted dashed line respectively represent the insertion loss of the low-frequency filter and the high-frequency filter in the prior art
  • the solid line marked by a small square and the solid line marked by a small circle respectively represent the ninth embodiment Insertion loss of low frequency filter and high frequency filter.
  • the out-of-band suppression characteristics of the low-frequency filter are significantly improved in the AL, BL, and CL regions.
  • the out-of-band suppression characteristics of the high-frequency filter are The AH area, BH area and CH area have all improved significantly.
  • Fig. 31 is an enlarged schematic diagram of the area A-L and the area A-H in Fig. 30.
  • Fig. 32 is a schematic diagram of the comparison of the isolation characteristics of the duplexer in the ninth embodiment of the present invention and the prior art. As shown in Fig. 31 and Fig. 32, the main resonance frequency of the resonator P01 is set in the passband frequency band of the high-frequency filter.
  • the main resonance frequency of the resonator P02 is within the passband of the low-frequency filter, which can effectively improve the out-of-band suppression characteristics of the high-frequency filter in the passband of the low-frequency filter and the isolation of the passband of the low-frequency filter.
  • Characteristics (the area shown by AH in Fig. 31 and the area shown by DH in Fig. 32).
  • the SC circuit is connected in parallel at a certain node of the series path of the ladder filter, and the resonator in the SC circuit includes the main resonance and the high-order resonance.
  • the main resonance frequency and the high-order resonance frequency of the resonator are They are all outside the passband of the filter, and the series resonance point of the main resonance and the high-order resonance will form a suppression zero point outside the band, thereby improving the out-of-band suppression characteristics of the filter.
  • the series resonance frequency point of the equivalent capacitance of the resonator and the inductance cascaded with it is set near the frequency band where the filter out-of-band suppression needs to be improved (including the frequency band where the filter high-order resonance is located).
  • Both the low-frequency filter and the high-frequency filter in the duplexer can be added to the above-mentioned SC circuit.
  • the SC circuit in the low-frequency filter is called the LSC circuit
  • the SC circuit in the high-frequency filter is called the HSC circuit.
  • the main resonance frequency and high-order resonance frequency of the resonator in the LSC circuit are required to be outside the passband of the low-frequency filter (it can be at the high-frequency end of the passband or at the low-frequency end of the passband.
  • the mass load can be set on the resonator. At the high-frequency end of the pass band, the resonator can be set on the chip where the high-frequency filter is located.
  • the high-frequency filter When it is set on the chip where the high-frequency filter is located, the high-frequency filter can be passed. Band frequency isolation improvement; the main resonance frequency and high-order resonance frequency of the resonator in the HSC circuit are required to be outside the passband of the high-frequency filter (the high-frequency end of the passband can also be at the low-frequency end of the passband),
  • the resonator in the HSC circuit is set on the chip where the low-frequency filter is located or the mass load is set on the resonator so that the main resonance frequency is within the passband of the low-frequency filter, so as to realize the isolation of the passband of the low-frequency filter. improve.

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Abstract

本发明公开了一种滤波器、双工器、多工器以及通信设备，该滤波器为梯形结构，包括1条串联路径和多个并联支路，该滤波器中的谐振器为声波谐振器，其特征在于，所述多个并联支路中包含1个SC电路，并且：该SC电路中包含1个谐振器和串联的电感器，该SC电路中的谐振器的主谐振频率和高次谐振频率均位于所述滤波器的通带以外；或者，该SC电路中包含谐振器组和串联的电感器，该谐振器组包含多个谐振器，其中至少有一个谐振器的谐振频率与其他谐振器的谐振频率不同，且其中每一个谐振器的主谐振频率和高次谐振频率均在所述滤波器的通带以外。采用本发明的技术方案，有助于提高滤波器和多工器的高次谐振的抑制度，同时提高多工器的隔离度。

Description

滤波器、双工器、多工器以及通信设备 技术领域
本发明涉及滤波器技术领域，特别地涉及一种滤波器、双工器、多工器以及通信设备。
背景技术
近年来的通信设备小型化和高性能趋势的加快，给射频前端提出了更高的挑战。在射频通信前端中，一方面要通过减小芯片和封装基板的尺寸来实现小型化，另一方面要通过减少损耗来源以及更好的谐振器配合设计来实现更好的性能。在现有的滤波器结构中，用于匹配的无源器件较多，同时用于改善特定性能比如滚降插损等也需要额外引入更多的电感、电容、耦合等多种结构。
普通的滤波器的一种典型结构如图1所示，图1是根据现有技术中的声波滤波器的一种结构的示意图。这种滤波器100中，输入端T1和输出端T2之间有电感L1、L2以及多个谐振器(通常称作串联谐振器)S11～S14，各串联谐振器的连接点与接地端之间的多个支路(通常称作并联支路)上分别设置有谐振器P12～P14(通常称作并联谐振器)，以及电感L3～L5。各并联谐振器上添加有质量负载层，使并联谐振器的频率和串联谐振器的频率具有差异从而形成滤波器的通带。
图2为传统的薄膜体声波谐振器的切面示意图。如图2所示，薄膜体声波谐振器300中，31是半导体衬底材料，35是通过刻蚀得到的空气腔，薄膜体声波谐振器的底电极33淀积于半导体衬底31之上，32为压电薄膜材料，34为顶电极。虚线框选区域为35空气腔、34顶电极、33底电极和32压电层的重叠区域，此为谐振有效区。其中，顶电极和底电极的材料可以由金(Au)、钨(W)、钼(Mo)、铂(Pt)、钌(Ru)、铱(Ir)、钛钨(TiW)、 铝(Al)、或钛(Ti)等类似金属形成；压电层的材料可以为氮化铝(AlN)、氧化锌(ZnO)、锆钛酸铅(PZT)、铌酸锂(LiNbO3)、石英(Quartz)、铌酸钾(KNbO3)或钽酸锂(LiTaO3)等。压电薄膜的厚度一般小于10微米。氮化铝薄膜为多晶形态或者单晶形态，生长方式为薄膜溅射(sputtering)或者有机金属化学气相沉积法(MOCVD)。
图3为根据现有技术中的体声波谐振器(BAW)的阻抗频率特性示意图。BAW谐振器的主谐振存在两个谐振频点：一个是谐振电路阻抗值达到极小值时的fs，将fs定义为该谐振器的串联谐振频点；另一个是当谐振电路阻抗值达到极大值时的fp，将fp定义为该谐振器的并联谐振频点。如图3所示，由于BAW谐振器本身结构特点，BAW谐振器在产生主谐振的同时会在高频端产生高次谐振，这种高次谐振通常是不需要的并且应当对其进行抑制。
图4为根据现有技术的双工器的电路架构的示意图。如图4所示，现有技术中的一种双工器102中，虚线框D1为双工器低频滤波器芯片，虚线框D2为双工器高频滤波器芯片。低频滤波器和高频滤波器均为梯型结构压电滤波器。低频滤波器中包含串联谐振器S11至S14、并联谐振器P11至P13。高频滤波器中包含串联谐振器S21至S24、并联谐振器P21至P24。L1和L2为低频滤波器信号输入输出端电感，L5和L6为高频滤波器信号输入输出端电感，L3和L4为低频滤波器的并联支路接地电感，L7和L8为高频滤波器的并联支路的接地电感。LM为双工器天线端匹配电感。
发明内容
有鉴于此，本发明提供一种滤波器、双工器、多工器以及通信设备，利用特殊谐振器与电感串联形成的SC电路改善滤波器的带外抑制性能，并改善双工器和多工器的隔离度。
根据本发明的第一方面，提供了一种滤波器。
本发明的滤波器为梯形结构，包括1条串联路径和多个并联支路，该滤波器中的谐振器为声波谐振器，所述多个并联支路中包含1个SC电路，并且：该SC电路中包含1个谐振器和串联的电感器，该SC电路中的谐振器的主谐振频率和高次谐振频率均位于所述滤波器的通带以外；或者，该SC电路中包含谐振器组和串联的电感器，该谐振器组包含多个谐振器，其中至少有一个谐振器的谐振频率与其他谐振器的谐振频率不同，且其中每一个谐振器的主谐振频率和高次谐振频率均在所述滤波器的通带以外。
可选地，所述1个谐振器或所述谐振器组的等效电容，与所述串联的电感器形成的串联谐振的频率位于所述滤波器的带外抑制频段。
根据本发明的第二方面，提供了第一种双工器，该双工器包括低频滤波器和高频滤波器，该双工器中的高频滤波器为本发明所述的滤波器。
可选地，所述主谐振频率在该双工器的高频滤波器的通带外。
可选地，所述SC电路中的谐振器或谐振器组设置在高频滤波器所在芯片，该谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在高频滤波器的通带外的低频端。
可选地，所述SC电路中的谐振器或谐振器组设置在低频滤波器所在芯片，该谐振器或谐振器组中的各膜层厚度与低频滤波器中串联谐振器的膜层厚度相同或相近，使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器通带内。
可选地，高频滤波器中的SC电路连接于双工器的高频滤波器信号输入/输出端或高频滤波器串联路径的某一个节点。
根据本发明的第三方面，提供了第二种双工器，该双工器包括低频滤波器和高频滤波器，该双工器中的低频滤波器为本发明所述的滤波器。
本发明的该双工器包括低频滤波器和高频滤波器，该双工器中的低频滤波器为本发明所述的滤波器。
可选地，所述主谐振频率在该双工器的低频滤波器的通带外。
可选地，所述SC电路中的谐振器或谐振器组设置在低频滤波器所在芯片，该谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器的通带外的低频端。
可选地，所述SC电路中的谐振器或谐振器组设置在高频滤波器所在芯片，该谐振器或谐振器组中的各膜层厚度与高频滤波器中串联谐振器的膜层厚度相同或相近，使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在高频滤波器通带内。
可选地，低频滤波器中的SC电路连接于双工器的低频端滤波器信号输入/输出端或低频滤波器串联路径的某一个节点。
根据本发明的第四方面，提供了第三种双工器，该双工器包括低频滤波器和高频滤波器，该双工器中的高频滤波器和低频滤波器皆为本发明所述的滤波器。
可选地，低频滤波器中的所述SC电路的谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率位于低频滤波器通带外。
可选地，高频滤波器中的所述SC电路的谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率位于高频滤波器的通带外。
可选地，低频滤波器中的所述SC电路中的谐振器或谐振器组设置在低频滤波器所在芯片，该谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器的通带外的低频端；高频滤波器中的所述SC电路中的谐振器或谐振器组设置在高频 滤波器所在芯片，该谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器的通带内。
可选地，低频滤波器和高频滤波器中的所述SC电路中的谐振器或谐振器组皆设置在低频滤波器所在芯片；低频滤波器的所述SC电路中的谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器的通带外的低频端；高频滤波器的所述SC电路中的谐振器或谐振器组中的各膜层厚度与低频滤波器中串联谐振器的膜层厚度相同或相近，使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器通带内。
可选地，低频滤波器中的所述SC电路中的谐振器或谐振器组，设置在高频滤波器所在芯片并且各膜层厚度与高频滤波器中串联谐振器的膜层厚度相同或相近；高频滤波器中的所述SC电路中的谐振器或谐振器组，设置在低频滤波器所在芯片并且各膜层厚度与低频滤波器中串联谐振器的膜层厚度相同或相近。
可选地，高频滤波器中的SC电路连接于双工器的高频滤波器信号输入/输出端或高频滤波器串联路径的某一个节点；低频滤波器中的SC电路连接于双工器的低频端滤波器信号输入/输出端或低频滤波器串联路径的某一个节点。
根据本发明的第五方面，提供了一种多工器，该多工器包括本发明所述的滤波器或双工器。
根据本发明的第六方面，提供了一种通信设备，该通信设备包括本发明所述的滤波器或双工器。
附图说明
为了说明而非限制的目的，现在将根据本发明的优选实施例、特别是参考附图来描述本发明，其中：
图1是根据现有技术中的声波滤波器的一种结构的示意图；
图2为传统的薄膜体声波谐振器的切面示意图；
图3为根据现有技术中的体声波谐振器(BAW)的阻抗频率特性示意图；
图4为根据现有技术的双工器的电路架构的示意图；
图5是根据本发明实施方式的用于抑制体声波谐振器高次谐振的电路的基本结构示意图；
图6是根据本发明实施方式的谐振器阻抗特性曲线与SC电路阻抗特性曲线的示意图；
图7是本发明第一实施例中的滤波器的电路结构的示意图；
图8是本发明第一实施例中的滤波器的插损频率特性(实线)与作为对比例一的现有技术所示滤波器的插损频率特性(虚线)的对比；
图9是本发明第一实施例中的滤波器的插损频率特性(实线)与SC电路的阻抗特性(虚线)的对比；
图10是根据本发明第二实施例中的滤波器的电路结构的示意图；
图11是根据本发明第三实施例的双工器的电路结构的示意图；
图12是根据本发明第四实施例的双工器的电路结构的示意图；
图13是根据本发明第三实施例和第四实施例所示双工器电路的插损频率特性的示意图；
图14是图13中的A区域放大的示意图；
图15是本发明第三实施例和第四实施例与现有技术的隔离度特性对比的示意图；
图16是根据本发明第五实施例的双工器的电路结构的示意图；
图17是本发明第五实施例所示双工器电路的插损频率特性的示意图；
图18是图17中A区域放大的示意图；
图19是图17中B区域和C区域放大的示意图；
图20是根据本发明第六实施例的双工器的电路结构的示意图；
图21是根据本发明第六实施例所示双工器电路的插损频率特性的示意图；
图22是21的A区域放大的示意图；
图23为本发明第六实施例与现有技术中的双工器隔离度特性对比的示意图；
图24是根据本发明第七实施例的双工器的电路结构的示意图；
图25是根据本发明第八实施例的双工器的电路结构的示意图；
图26是根据本发明第七实施例和第八实施例所示双工器电路的频率插损特性的示意图；
图27是图26中的A-L区域和A-H区域的放大示意图；
图28为本发明第七、第八实施例与现有技术中的双工器隔离度特性对比的示意图；
图29是根据本发明第九实施例的双工器的电路结构的示意图；
图30是根据本发明第九实施例所示双工器电路的插损频率特性的示意图；
图31是图30中的A-T区域和A-R区域的放大示意图；
图32是本发明第九实施例与现有技术中的双工器隔离度特性对比的示意图。
具体实施方式
本发明实施方式中，采用谐振器与电感串联的电路对体声波谐振器的高次谐振进行抑制。这种电路的基本结构如图5所示，图5是根据本发明实施方式的用于抑制体声波谐振器高次谐振的电路的基本结构示意图。在以下的描述中，将图5中的电路称作SC电路。并且需要说明的是，为了便于描述，当该电路应用于双工器中的高频滤波器时，该电路也称作HSC电路，当该电路应用于双工器中的低频滤波器时，该电路也称作LSC电路。
图5中示出了SC电路包含1个谐振器P01和1个串联的电感(电感器)LS。在实际应用时，该谐振器P01可以是多个谐振器连接(包括串联和/或并联)构成的谐振器组，电感LS也可以是多个电感的串联和/或并联体，这样，串联的电感则是指串联和/或并联体与单个谐振器串联或与谐振器组串联。
利用SC电路对谐振器高次谐振进行抑制的原理可以参考图6，图6是根据本发明实施方式的谐振器阻抗特性曲线与SC电路阻抗特性曲线的示意图。图中实线表示SC电路阻抗，虚线表示单个谐振器阻抗。SC电路的特点在于SC电路中的谐振器P01的谐振频点(包括主谐振和高次谐振)设置在滤波器通带以外。通过设置合适的谐振器P01的面积和电感值，使得谐振器P01的平板电容和与之级联的LS电感形成的串联谐振频点发生在滤波器需改善的带外抑制所在频段。在图6中，将该两个曲线置于同一坐标系下进行对比，可以看出，实线所示SC电路的阻抗在谐振器P01的平板电容和与之级联的LS电感形成的串联谐振频点附近为极小值，因此SC电路在高频端产生的串联谐振可有效改善所在频段的抑制特性。
SC电路在串联谐振频点确定的前提下，谐振器P01的平板电容和与之级联的LS电感的乘积就随之确定，平板电容越大LS以及电感越小时，SC电路对滤波器高频端带外抑制改善越明显，对通带插损影响越大；平板电容越小以及LS电感越大时，SC电路对滤波器高频端带外抑制改善程度越小，对通带插损影响越小。故谐振器P01的面积和LS电感需根据通带插损和带外抑制指标权衡设计。
图7是本发明第一实施例中的滤波器的电路结构的示意图。如图7所示，滤波器600是主要由串联谐振器S11～S14、并联谐振器P12～P14和SC电路组成的梯型结构压电滤波器。图中T1为信号输入端口，T2为信号输出端口，L1和L2为输入端电感和输出端电感，L3、L4和L5为并联支路接地电感。图中的SC电路一端接地，另一端可以连接在滤波器串联支路中的任一节点。
图8是本发明第一实施例中的滤波器的插损频率特性(实线)与作为对比例一的现有技术所示滤波器的插损频率特性(虚线)的对比。由图8可见，相比现有技术，第一实施例中的滤波器在A区域、B1区域、B2区域和C区域处带外抑制均有明显改善。
图9是本发明第一实施例中的滤波器的插损频率特性(实线)与SC电路的阻抗特性(虚线)的对比。从图9可以看出SC电路是如何影响滤波器性能。如图9所示，A区域对应SC电路中谐振器P01主谐振的串联谐振频点附近频段，B1区域对应SC电路中谐振器P01第一高次谐振的串联谐振频点附近频段，B2区域对应SC电路中谐振器P01第二高次谐振的串联谐振频点附近频段，C区域对应SC电路中谐振器P01的平板电容和与之级联的LS电感形成的串联谐振频点附近频段。即本发明中的SC电路中谐振器的主谐振、高次谐振以及谐振器的平板电容和与之级联的电感的串联谐振均被合理利用来提升器件的整体性能。
对于SC电路，如前所述，其中的谐振器可以是多个的连接体，这种方式的具体应用示例于图10，图10是根据本发明第二实施例中的滤波器的电路结构的示意图。如图10所示，第二实施例第一实施例区别在于SC电路中谐振器的结构。第二实施例将SC电路中的谐振器进行串联拆分，可为等面积拆分亦可为非等面积拆分，但是谐振器P01和谐振器P02的主谐振频率不同。对于双工器，其中的低频滤波器和/或高频滤波器可以应用上述的包含SC电路的滤波器，以下具体进行说明。
图11是根据本发明第三实施例的双工器的电路结构的示意图。如图11所示，在高频滤波器中设置SC电路(HSC电路)，HSC可以并联设置在高频滤波串联路径的任意一个节点上，但是最好设置在如图11所示位置，因为HSC电路距离双工器的天线端越远对双工器的收敛性影响越小。HSC电路中的谐振器P02可以通过加质量负载进行移频，使其主谐振频率设置在高频滤波器通带外的低频端，并且特别地，其主谐振频率可设置到低频滤波器的通带内。
图12是根据本发明第四实施例的双工器的电路结构的示意图。如图12所示，HSC电路中的谐振器P02亦可以设置在低频滤波器的芯片上，HSC电路中谐振器的堆叠结构(stack)中各膜层厚度与低频滤波器中串联谐振器的膜层厚度相同或相近，使其主谐振频率在高频滤波器通带外的低 频端(包括低频滤波器通带所在频段)。
图13是根据本发明第三实施例和第四实施例所示双工器电路的插损频率特性的示意图，并将实施例中高频滤波器的插损频率特性与作为对比例二的现有技术的双工器中高频滤波器的插损频率特性进行了对比。图中，小方框标示的实线为第三实施例、第四实施例以及现有技术中的低频滤波器的插损曲线，因未添加SC电路，因此三者曲线一致。小圆圈标示的实线为第三实施例、第四实施例的高频滤波器的插损曲线，虚线为现有技术中的高频滤波器的插损曲线，未带标示的实线为第三实施例和第四实施例中HSC电路的阻抗频率特性，A区域抑制对应HSC电路中谐振器的主谐振，B区域抑制对应HSC电路中谐振器的高次谐振，C区与抑制对应HSC电路中谐振器P02的平板电容和与之级联的电感形成的串联谐振。由图可见，对于第三实施例和第四实施例中的电路结构，由于设置HSC电路，其高频滤波器的带外抑制特性在A区域、B区域和C区域均有明显改善。
图14是图13中的A区域放大的示意图，图15是本发明第三实施例和第四实施例与现有技术的隔离度特性对比的示意图。如图14、图15所示，如果HSC电路中谐振器的主谐振落设置在低频滤波器的通带内，可以有效改善高频滤波器在低频滤波器通带所在频段的带外抑制特性(图14中A区域所示)以及低频滤波器通带所在频段的隔离度特性(图15中D区域所示)。
图16是根据本发明第五实施例的双工器的电路结构的示意图。如图16所示，在低频滤波器中设置LSC电路，LSC可以并联设置在低频滤波串联路径的任意一个节点上，但是最好设置如图16所示位置，因为LSC电路距离双工器的天线端越远对双工器的收敛性影响越小。LSC电路中的谐振器P01可以通过设置质量负载进行移频，使其主谐振频率在低频滤波器通带外的低频端。
图17是本发明第五实施例所示双工器电路的插损频率特性的示意图， 并将第五实施例中低频滤波器的插损频率特性与现有技术中低频滤波器的插损频率特性进行了对比。图18是图17中A区域放大的示意图。图19是图17中B区域和C区域放大的示意图。各图中，虚线为现有技术中的低频滤波器的插损曲线，小方框标示的实线为第五实施例和现有技术中的高频滤波器的插损曲线，小圆圈标示的实线为第五实施例中低频滤波器的插损曲线，未带标示的实线为第五实施例中LSC电路的阻抗频率特性，A区域抑制对应LSC电路中谐振器的主谐振，B区域抑制对应LSC电路中谐振器的高次谐振，C区与抑制对应LSC电路中谐振器P01的平板电容和与之级联的电感形成的串联谐振。由图可见，第五实施例中的双工器，由于设置LSC电路，其低频滤波器的带外抑制特性在A区域、B区域和C区域均有明显改善。
图20是根据本发明第六实施例的双工器的电路结构的示意图。如图20所示，在低频滤波器中设置LSC电路，LSC可以并联设置在低频滤波串联路径的任意一个节点上，但是最好设置如图20所示位置。LSC电路中的谐振器P01做在高频滤波器芯片上，LSC电路中谐振器的Stack各膜层厚度与高频滤波器中串联谐振器的膜层厚度相同或相近，使其主谐振频率在高频滤波器通带内。
图21是根据本发明第六实施例所示双工器电路的插损频率特性的示意图，并将第六实施例中低频滤波器的插损频率特性与现有技术中低频滤波器的插损频率特性进行了对比。图中虚线为现有技术中低频滤波器插损曲线，小方框标示的实线为第六实施例与现有技术中高频滤波器的插损曲线，小圆圈标示的实线为第六实施例中低频滤波器的插损曲线，未带标示的实线为第六实施例中LSC电路的阻抗频率特性，A区域抑制对应LSC电路中谐振器的主谐振，B区域抑制对应LSC电路中谐振器的高次谐振，C区与抑制对应LSC电路中谐振器P01的平板电容和与之级联的电感形成的串联谐振。由图可见，第六实施例中的双工器由于设置LSC电路，其低频滤波器的带外抑制特性在A区域、B区域和C区域均有明显改善。
图22是21的A区域放大的示意图。图23为本发明第六实施例与现有技术中的双工器隔离度特性对比的示意图，图中虚线对应现有技术，小圆圈标示的实线对应第六实施例。如图22和图23所示，谐振器P01的主谐振频率在高频滤波器通带频段内，可以有效改善低频滤波器在高频滤波器通带所在频段的带外抑制特性(图22中A区域所示)以及高频滤波器通带所在频段的隔离度特性(图23中D区域所示)。
图24是根据本发明第七实施例的双工器的电路结构的示意图。如图24所示，在低频滤波器中设置LSC电路，同时在高频滤波器中设置HSC电路。LSC电路可以并联设置在低频滤波串联路径的任意一个节点上，HSC电路可以并联设置在高频滤波串联路径的任意一个节点上，但较佳的方式是，LSC电路和HSC电路设置如图24所示远离双工器天线端位置，这样对双工器的收敛性影响较小。LSC电路中的谐振器P01做在低频滤波器芯片上，通过加质量负载使其主谐振频率在低频滤波器通带外的低频端，HSC电路中的谐振器P02做在高频滤波器芯片上，通过加质量负载使其主谐振在高频滤波器通带外的低频端，特别地，其主谐振频率可以设置到低频滤波器通带内。
图25是根据本发明第八实施例的双工器的电路结构的示意图。与第七实施例不同点在于，第八实施例中的HSC电路做在低频滤波器芯片上，HSC电路中谐振器的Stack各膜层厚度与低频滤波器中串联谐振器的膜层厚度相同或相近，使其主谐振在低频滤波器通带内。
图26是根据本发明第七实施例和第八实施例所示双工器电路的频率插损特性的示意图，并将其插损频率特性与现有技术中的双工器进行了对比。由图可见，第七实施例和第八实施例的双工器由于设置LSC电路和HSC电路，低频滤波器的带外抑制特性在A-L区域、B-L区域和C-L区域均有明显改善，同时，高频滤波器的带外抑制特性在A-H区域、B-H区域和C-H区域均有明显改善。
图27是图26中的A-L区域和A-H区域的放大示意图。图28为本发明第七、第八实施例与现有技术中的双工器隔离度特性对比的示意图，图中未标示的实线对应现有技术，小圆圈标示的实线对应第七实施例。如图27和图28所示，谐振器P02的主谐振频率设置在低频滤波器通带频段内，可以有效改善高频滤波器在低频滤波器通带所在频段的带外抑制特性(图27中A-H区域所示)以及低频滤波器通带所在频段的隔离度特性(图28中D-H区域所示)。
图29是根据本发明第九实施例的双工器的电路结构的示意图。如图9所示，在低频滤波器中设置LSC电路，同时在高频滤波器中设置HSC电路。LSC电路可以并联设置在低频滤波串联路径的任意一个节点上，HSC电路可以并联设置在高频滤波串联路径的任意一个节点上，但是较佳的方式是LSC电路和HSC电路设置如图29所示远离双工器天线端位置。LSC电路中的谐振器P01设置在高频滤波器芯片上，HSC电路中的谐振器P02设置在低频滤波器芯片上。特别地，LSC电路中谐振器P01的主谐振频率设置在高频滤波器通带内，HSC电路中谐振器P02的主谐振频率设置在低频滤波器通带内。
图30是根据本发明第九实施例所示双工器电路的插损频率特性的示意图，并将其插损频率特性与现有技术进行了对比。图30中，短线状虚线和点状虚线分别表示现有技术中的低频滤波器和高频滤波器插损，小方框标示的实线和小圆圈标示的实线分别表示第九实施例的低频滤波器和高频滤波器插损。由图可见，第九实施例由于设置LSC电路和HSC电路，低频滤波器的带外抑制特性在A-L区域、B-L区域和C-L区域均有明显改善，同时，高频滤波器的带外抑制特性在A-H区域、B-H区域和C-H区域均有明显改善。
图31是图30中的A-L区域和A-H区域的放大示意图。图32是本发明第九实施例与现有技术中的双工器隔离度特性对比的示意图，如图31和图32所示，谐振器P01的主谐振频率设置在高频滤波器通带频段内， 可以有效改善低频滤波器在高频滤波器通带所在频段的带外抑制特性以及高频滤波器通带所在频段的隔离度特性(图31中A-L所示区域和图32中D-L所示区域)，谐振器P02的主谐振频率在低频滤波器通带频段内，可以有效改善高频滤波器在低频滤波器通带所在频段的带外抑制特性以及低频滤波器通带所在频段的隔离度特性(图31中A-H所示区域和图32中D-H所示区域)。
根据本发明实施方式的技术方案，在梯形滤波器的串联路径的某一个节点上并联连接SC电路，SC电路中谐振器包括主谐振和高次谐振，该谐振器主谐振频率和高次谐振频率都在滤波器通带以外，主谐振和高次谐振的串联谐振点会在带外形成抑制零点，从而提升滤波器的带外抑制特性。另外，谐振器的等效电容和与之级联的电感的串联谐振频点设置在需改善的滤波器带外抑制所在频段附近(包括滤波器高次谐振所在频段)。在双工器中低频滤波器和高频滤波器均可加入上述SC电路，低频滤波器中的SC电路称为LSC电路，高频滤波器中的SC电路称为HSC电路。LSC电路中的谐振器的主谐振频点和高次谐振频点要求在低频滤波器通带以外(可在通带高频端亦可在通带低频端，在通带低频端时可通过在谐振器上设置质量负载实现，在通带高频端时可通过把谐振器设置在高频滤波器所在芯片上)，设置在高频滤波器所在芯片上时，可以实现对高频滤波器通带频段隔离度的改善；HSC电路中的谐振器的主谐振频点和高次谐振频点要求在高频滤波器通带以外(可在通带高频端亦可在通带低频端)，HSC电路中的谐振器设置在低频滤波器所在芯片上或通过所述谐振器上设置质量负载使其主谐振频点在低频滤波器通带内，从而实现对低频滤波器通带频段隔离度的改善。
上述具体实施方式，并不构成对本发明保护范围的限制。本领域技术人员应该明白的是，取决于设计要求和其他因素，可以发生各种各样的修改、组合、子组合和替代。任何在本发明的精神和原则之内所作的修改、等同替换和改进等，均应包含在本发明保护范围之内。

Claims (21)

  1. 一种滤波器，该滤波器为梯形结构，包括1条串联路径和多个并联支路，该滤波器中的谐振器为声波谐振器，其特征在于，所述多个并联支路中包含1个SC电路，并且：
    该SC电路中包含1个谐振器和串联的电感器，该SC电路中的谐振器的主谐振频率和高次谐振频率均位于所述滤波器的通带以外；
    或者，
    该SC电路中包含谐振器组和串联的电感器，该谐振器组包含多个谐振器，其中至少有一个谐振器的谐振频率与其他谐振器的谐振频率不同，且其中每一个谐振器的主谐振频率和高次谐振频率均在所述滤波器的通带以外。
  2. 根据权利要求1所述的滤波器，其特征在于，所述1个谐振器或所述谐振器组的等效电容，与所述串联的电感器形成的串联谐振的频率位于所述滤波器的带外抑制频段。
  3. 一种双工器，该双工器包括低频滤波器和高频滤波器，其特征在于，该双工器中的高频滤波器为权利要求1或2所述的滤波器。
  4. 根据权利要求3所述的双工器，其特征在于，所述主谐振频率在该双工器的高频滤波器的通带外。
  5. 根据权利要求3或4所述的双工器，其特征在于，所述SC电路中的谐振器或谐振器组设置在高频滤波器所在芯片，该谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在高频滤波器的通带外的低频端。
  6. 根据权利要求3或4所述的双工器，其特征在于，所述SC电路中的谐振器或谐振器组设置在低频滤波器所在芯片，该谐振器或谐振器组中 的各膜层厚度与低频滤波器中串联谐振器的膜层厚度相同或相近，使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器通带内。
  7. 根据权利要求3所述的双工器，其特征在于，高频滤波器中的SC电路连接于双工器的高频滤波器信号输入/输出端或高频滤波器串联路径的某一个节点。
  8. 一种双工器，该双工器包括低频滤波器和高频滤波器，其特征在于，该双工器中的低频滤波器为权利要求1或2所述的滤波器。
  9. 根据权利要求8所述的双工器，其特征在于，所述主谐振频率在该双工器的低频滤波器的通带外。
  10. 根据权利要求8或9所述的双工器，其特征在于，所述SC电路中的谐振器或谐振器组设置在低频滤波器所在芯片，该谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器的通带外的低频端。
  11. 根据权利要求8或9所述的双工器，其特征在于，所述SC电路中的谐振器或谐振器组设置在高频滤波器所在芯片，该谐振器或谐振器组中的各膜层厚度与高频滤波器中串联谐振器的膜层厚度相同或相近，使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在高频滤波器通带内。
  12. 根据权利要求8所述的双工器，其特征在于，低频滤波器中的SC电路连接于双工器的低频端滤波器信号输入/输出端或低频滤波器串联路径的某一个节点。
  13. 一种双工器，该双工器包括低频滤波器和高频滤波器，其特征在 于，该双工器中的高频滤波器和低频滤波器皆为权利要求1或2所述的滤波器。
  14. 根据权利要求13所述的双工器，其特征在于，低频滤波器中的所述SC电路的谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率位于低频滤波器通带外。
  15. 根据权利要求13所述的双工器，其特征在于，高频滤波器中的所述SC电路的谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率位于高频滤波器的通带外。
  16. 根据权利要求13、14或15中任一项所述的双工器，其特征在于，
    低频滤波器中的所述SC电路中的谐振器或谐振器组设置在低频滤波器所在芯片，该谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器的通带外的低频端；
    高频滤波器中的所述SC电路中的谐振器或谐振器组设置在高频滤波器所在芯片，该谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器的通带内。
  17. 根据权利要求13、14或15中任一项所述的双工器，其特征在于，
    低频滤波器和高频滤波器中的所述SC电路中的谐振器或谐振器组皆设置在低频滤波器所在芯片；
    低频滤波器的所述SC电路中的谐振器或谐振器组中的质量负载使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器的通带外的低频端；
    高频滤波器的所述SC电路中的谐振器或谐振器组中的各膜层厚度与低频滤波器中串联谐振器的膜层厚度相同或相近，使该谐振器的主谐振频率或谐振器组中各谐振器的主谐振频率在低频滤波器通带内。
  18. 根据权利要求17所述的双工器，其特征在于，
    低频滤波器中的所述SC电路中的谐振器或谐振器组，设置在高频滤波器所在芯片并且各膜层厚度与高频滤波器中串联谐振器的膜层厚度相同或相近；
    高频滤波器中的所述SC电路中的谐振器或谐振器组，设置在低频滤波器所在芯片并且各膜层厚度与低频滤波器中串联谐振器的膜层厚度相同或相近。
  19. 根据权利要求13所述的双工器，其特征在于，
    高频滤波器中的SC电路连接于双工器的高频滤波器信号输入/输出端或高频滤波器串联路径的某一个节点；
    低频滤波器中的SC电路连接于双工器的低频端滤波器信号输入/输出端或低频滤波器串联路径的某一个节点。
  20. 一种多工器，其特征在于，包括权利要求1至19中任一项所述的滤波器或双工器。
  21. 一种通信设备，其特征在于，包括权利要求1至19中任一项所述的滤波器或双工器。
PCT/CN2021/095993 2020-05-28 2021-05-26 滤波器、双工器、多工器以及通信设备 WO2021238970A1 (zh)

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